Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [smith-chart]

A graphical chart, named after the electrical engineer Phillip H. Smith, designed to help solve problems with transmission lines and impedance matching. Consider using this tag along with the "transmission-line", "impedance", "impedance-matching", "characteristic-impedance", and/or "rf" tags, as appropriate.

A graphical chart, named after the electrical engineer Phillip H. Smith, designed to help solve problems with transmission lines and impedance matching. Consider using this tag along with , , , , and/or , as appropriate.

46 questions
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Balun/matching network question

I am having problem to verify what an app note (AN068) explains to calculate Balun values. I would appreciate if someone could tell me what/where am I doing wrong? The summary of the RF part: Blue part is the DC blocking cap, C10-L1 and L3-C11 are…
Angs
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Smith Chart Explanation

I'm working on designing some hopefully simple RF (912 MHz) attenuators. I need a few different levels of attenuation but each different attenuator can be fixed. I have prototyped one using just off the shelf resistors in a T-pad configuration that…
NickHalden
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Wideband Impedance Matching

I have designed a common-emitter RF amplifier, with input and output impedance matched for my load and source impedance. I have used Smith Chart for the matching. The matching is good for the designed frequency, but when using other frequencies the…
JakobJ
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Smith Chart is giving me an answer I didn't expect - Am I using it right?

I'm trying to track down a VSWR issue with a RF power amplifier (25 W, 150 MHz). The radio we're using to drive it has a VSWR alarm, which triggers during transmit. Older manufacture runs of the PA don't trigger the VSWR alarm, and I'm not certain…
harry courtice
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What application do you use for plots?

What application do you use for creating plots? Years ago, I was using gnuplot and then matplotlib (which is just Python library). But none of those were perfect. For example, I was unable to create Smith chart in gnuplot or two Y axes in one plot.…
vasco
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Help with Matching circuit

I'm using a SAW filter which has balanced input and output. In the datasheet there is shown a matching application for 50ohms balanced output. But plotting the S22 parameters into a Smith Chart and trying to get the same matching circuit is not…
JakobJ
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RF amplifier load matching

I want to match RF power amp to aerial. There is no 50 ohm or 75 ohm transmission line inbetween. So, I consider my aim to be matching certain load-reflection coefficient (Γload) to a short circuit (no transmission line). Can I do it using a Smith…
ivan
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Is my VNA broken or miscalibrated, or are these weird results normal?

My company got a new vector network analyzer recently and I'm using it to try to learn more about microwave circuits, especially the resonant cavities that we use in our measurement systems. I've seen some unexpected behavior in simple situations…
Adam Haun
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Self-resonance frequency of chip inductors

I am studying chip inductors and here's one of the frequency responses: There is more than one resonance frequency for a single inductor. When we say inductor resonance frequency, it usually means the first one, right? Is there a specific name for…
Missfresstyle
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Finding unknown load using a smith chart

I am asked to find the impedance of an unknown load. The precise formulation is provided below: The following two step procedure was used to measure the value of an unknown load \$Z_{L}\$. The characteristic impedance of the feeding line is…
peripatein
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Smith Chart Conjugate Matching

In an example in Pozar's Microwave Engineering, a conjugate matching circuit for maximum gain is designed using Smith chart. In the shown Smith chart, the matching circuit for input is designed. We locate \$\Gamma_{source}\$ on the Smith chart,…
Dina Abdelhadi
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Use of Smith charts

There are Smith charts with impedance and admittance coordinates and Smith charts with only impedance coordinates. I believe I learned how to use the first one. Is there any sense in studying how to use the second one?
ivan
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Tuning an antenna using a NanoVNA, Smith chart and impedance readings

I am new to antenna design and teaching myself how to optimize antennas using a VNA. I have created a monopole antenna on a PCB (i.e. a single length of track.) The antenna can be fed via a PI network and is connected to my NanoVNA via an SMA…
Daveo
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How do I convert S-parameters for impedance matching?

How do I derive the Z-parameters to calculate a matching network for a device? I'm not sure what terms to even search for as I get all sorts of information I am not familiar with. My task is to construct a matching network for the MRF1535NT1 FET…
SubZero
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Calibrating a VNA

I am using the Siglent SSA3032A-R spectrum analyser which has a Vector Network Analyser (VNA). Before measuring the impedance of an antenna under test so that I can match this antenna, I have to calibrate the VNA. I perform a 1-port calibration,…
MRB
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